2-Alkyl-4-halo-5-formylimidazoles are important chemicals as mentioned above and are, therefore, attracting much attention in recent years However, there is little information on relevant production technology. The only pertinent literature (Japanese Laid-open Patent Application No. 54-148788) known to the inventors of the present invention describes a production process starting with, for example, 2-amino-3,3-dichloroacrylonitrile and an aldehyde and involving the corresponding Schiff base as an inter mediate.
This technology is disadvantageous in that the starting material 2-amino-3,3-dichloroacrylonitrile is not easily available with the result that commercial production is remarkedly handicapped. Therefore, the industry has been aspiring to finding a new production process for 2-alkyl-4-halo-5-formylimidazoles which can give these compounds in good yield from starting materials which are readily available.
After intensive research, the inventors of the present invention discovered a novel route of synthesis which comprises halogenating an 2-alkyl-4-halo-5-formylimidazole with an N-halosuccinimide. The present invention is predicated on the above finding.